Conventionally, as a combustion pressure sensor which detects a combustion pressure within the combustion chamber of an internal combustion engine, a pressure sensor disclosed in patent literature 1 is known.
The pressure sensor includes: a circular pressure reception diaphragm in which one surface is a pressure reception surface for receiving pressure to be measured and which is distorted by receiving the pressure to be measured on the pressure reception surface; a pressure transmission member in which one end portion is in contact with the other surface on the side opposite to the pressure reception surface of the pressure reception diaphragm; a sensor chip where a distortion sensing element is formed which is provided on the side of the other end portion opposite to the one end portion of the pressure transmission member and to which a force corresponding to the pressure to be measured received by the pressure reception diaphragm is applied through the pressure transmission member so as to generate the corresponding signal; and a cylindrical member which surrounds the pressure transmission member. In particular, as the basic structure, the pressure sensor has a structure in which a front end portion of a case formed with the cylindrical member and the pressure reception diaphragm are joined by welding and in which a pressure transmission portion located in a back end of the center portion of the pressure reception diaphragm is brought into contact with the pressure transmission member so as to transmit the force from the pressure transmission member to the sensor chip on the side of the back end where the distortion sensing element is formed.